import  numpy as np
import pandas as pd
arr = np.random.randint(1,20,size=(3,3))
df = pd.DataFrame(arr)
print(df)
print(df.sort_values(by=1,axis=1))
print(df.sort_values(by=1))
df.columns = ['a','b','c']
print(df)
print(df.sort_values(by='a',ascending=False))